Aircraft engine



April 9, 1940. R. A. l.. sELlGMAN y 2,196,340

AIRCRAFT ENGINE Filed Dec. 28, 1938 3 Sheets-Sheet l April 9, 1940. R. A, sELlGMAN AIRCRAFT ENGINE Filed Dec. 28, 1938 3 Sheets-Sheet 2 April 9, 1940. l R. A. L. sELlGMAN 2.196.340

I AIRCRAFT ENGINE Filed Dec., 28, 1958 3 Sheets-Sheet '3 l l L QL 9i 4 @all Il W w x l l C o o o M Patented Apr. 9, 1940 PATENT OFFICE AIRCRAFT ENGINE Roger Adolphe Leonard Seligman, Neuilly, Seine,

- u, ,France v Application'necember as, 193s, serial No. 248,100

l In France June 16, 1938 v u claims. (o1. 12s- 195) The fixing of engines on the fuselages of aircraft is generally obtained by means of an engine mounting which is secured' to the framework of the vaircraft and on which the crankn 5 case of the engine is bolted or otherwise removably fixed. l The present invention enables said `engine mounting to be eliminated. Said invention essentially consists in forming the crankcase of the engine in the 'shape of a rigid and undeformab-le box-girder which 'is provided on the one hand with means for receiving the cylinders and all the other members of lthe engine, and on'the other hand with -nieanswhich enable it to be directly-fixed on the framework of the aircraft, in place of the engine rnioiu'iting usually en played.` i According to an embodiment, said box-girder is formed yby two upper and lower horizontal plates, and two longitudinal side plateswhich are rigidly secured to the horizontal plates, the cylinders being fixed independently 'of each other inside said girder. n l

Said girder is provided on the inside with cross-pieces or partitions which separate the cylinders from each other'and perform the dual function, on the one handof reinforcing said girder, and on the other hand, in the case of air-cooled engines,A of forming compartments in which a current of air is set up in an appropriate manner. l This invention is applicable to all types of engines. However, its application is particularly advantageous in the 'case vof engines having as l known two opposed pistons in leach cylinder and,

consequently, two crankshafts.

In this particular application, the invention is characterized by the fact that the upper and lower horizontal plates, respectiveiy carry the 4,0 upper crankshaft and the lower crankshaft, the

parallelism of which is thus accurately maintained owing to the actual undeformability of the box-girder and without any special varrangement having to be provided for maintaining vsaid,

without any effect on the other members of they engine. i Other advantages and peculiarities of the iii- 55 vention will become apparent from the ensuing i description vtaken in conjunction -with the acsection, only'- the support for the' upper cranlrshaft being shown. v,

Fig. i is a plan View in partial section. v i

Fig. 5 is avtransverse section' passing-through '15 the longitudinal axis of one of the cylinders.

As shown in said drawings, the element which, according` to'I the invention,"simultaneously has to act asy a crankcase for the engine and a support for enabling same to [be fixed on the' 2.0`

framework ofan aircraft, comprises a boxgirder which vis formed by" a horizontal upper plate.y l, a lower horizontal platel 2, two side plates 3 and 4 and cross-pieces such as it, the'dis- 'tance betweenfwhich is equal to the distance ben 25 tween the axes of the cylinders. A'liliese four plates and cross-pieces, which are made for ex"` ample of steel plate, are rigidly assembled to, gether in, any appropriate manner. They may, for example, be riveted or welded together, the 30 rivetting is effected through the intermediary of angles isuch as'). v i The whole of the box-grder thus: formed may of course be of anyappropriate shape. Thus, in the example shown, the horizontalA plates l `and 35 2 are of generally trapezoidal shape.. At one of its ends, said boxgi'rder 'isl provided with lugs such as 6 at the end of each of which are providedh-theusual `means: for'ena-bling said" boxgirder tor be fixed tothe corresponding end of the framework of the'aircraft at four' points arranged atrthe corners of a rectangle, under the ,sameconditions as the engine mounting .is at present' fixed on theusual' aeroplanes, on which Aengine mounting is in turn fixed the crankcases of ordinary engines.

Inside said box-girder are fitted the cylinders 1` vof they engine (six cylinders in the example shown). In order to permit of the free expansion of said cylinders, each of same is rigidly fixed to the upper horizontal plate l by meansl for example of bolts 8 (Fig. 5), whereas at its` lower part said cylinder 'I can slide relatively to the lowerplate 2, a joint made of compressible material beingprovided at 9. 55

The cross-pieces I0 perform two functions. In the first place, they reinforce said box-girder and make it completely undeformable. In the second place, for air-cooled engines, and this is only accessory, they form in said box-girder a compartment for each cylinder, and in each of said compartments a current of cooling air can be set up. Forthis purpose, opposite each of said compartments, the side plates 3 and 4 are provided with openings such as II. The openings I I of one of the plates are provided with ears IIa which are directed in such a manner as to cause the air to flow into the corresponding compartment, whereas the orifices II of the opposite side plate are provided with ears IIa which enable the air to flow out. These ears IIal are shown in Figure 4. The incoming and outgoing flow of air is, or may be, as indicated by the arrows in Figure 4. The ears I Ia have been represented only for the first cylinder.

On the upper face of the upper horizontal plate I is provided a support such as I2 which is provided with bearings in which the upper crankshaft I3 rotates. Similarly, the lower face of the lower horizontal plate 2 is provided with a similar support, shown in dotted outline. The upper crankshaft and the lower crankshaft are respectively enclosed in appropriate crankcases, such as I4.

The box-girder according to the invention offers a large number of important advantages. In the first place, it alone replaces the usual crankcase of the engine and the supporting frame which is usually fitted on the framework of the aircraft. Furthermore, at the present time before fixing such a supporting frame on the framework of an aircraft, it is necessary to brace said framework so as to increase its rigidity. With the box-girder according to the invention, this previous bracing of the framework is useless since the box-girder, which is itself rigid and undeformable, ensures the bracing and the undeformability of said framework by the sole fact of its being fixed on same.

On the other hand, and still owing to its undeformability, said box-girder always ensures an absolute parallelism between the two crankshafts of the engine without its being necessary to provide particular arrangements for that purpose, as is required with the present known engines. Finally, by means of the above described mounting of the cylinders, the expansion of same can take place freely without having any effect on the other members of the engine.

It is moreover obvious that the invention has only been described and illustrated herein in an explanatory and non-limitative manner and that modications of detail may be made therein, without altering its spirit.

I claim:

1. A crankcase for aircraft engines, comprising a rigid and undeformable box-girder formed by two upper and lower horizontal plates, and two longitudinal side plates rigidly secured to said horizontal plates, means for fixing the cylinders inside said girder, and means for directly fixing said girder on the framework of the aircraft, in place of the usual engine mounting.

2. A crankcase for aircraft engines, comprising a rigid and undeformable box-girder formed by two upper and lower horizontal plates and two longitudinal side plates rigidly secured to said horizontal plates, means for fixing one of the ends of each cylinder to one of said horizontal plates, the other end of each cylinder being free to move relatively to the opposite plate, thereby allowing said cylinders to expand freely, and means for directly fixing said girder on the framework of the aircraft, in place of the usual engine mounting.

3. A crankcase for air-cooled aircraft engines, comprising a rigid undeformable box-girder formed by two upper and lower horizontal plates, two longitudinal side plates rigidly secured to said horizontal plates and reinforcing crosspieces forming a compartment for each cylinder, means for passing a current of cooling air through said compartments, means for fixing one of the ends of each cylinder to one of said horizontal plates, the other end of each cylinder being free to move relatively to the opposite plate, thereby allowing the cylinders to expand freely without aecting the other members of the engine, and means for directly fixing said girder on the framework of the aircraft, in place of the usual engine mounting.

4. A crankcase for engines which have opposed pistons and an upper and lower crankshaft, comprising a rigid undeformable box-girder formed by two upper and lower horizontal plates, and two longitudinal side plates, said two upper and lower horizontal plates respectively carrying the upper and the lower crankshaft, thereby maintaining an absolute parallelism of said crankshafts owing to the undeformable structure of said box-girder, means for fixing the cylinders independently of each other inside said girder, lugs formed at one end of said girder, and means on said lugs for fixing said girder to the framework of the aircraft, in place of the usual engine mounting.

5. A crankcase for aircraft engines which have opposed pistons and an upper and lower crankshaft, comprising a rigid undeformable boxgirder formed by two upper and lower horizontal plates, two longitudinal side plates and reinforcing cross-pieces between said upper and lower horizontal plates, said cross-pieces forming a compartment for each cylinder, means for passing a current of cooling air through said compartments, said two upper and lower horizontal plates respectively carrying the upper and lowerl crankshaft, means for fixing one of the ends of each cylinder to one of said horizontal plates, the other end thereof being free to move relatively to the opposite plate, thereby allowing the cylinders to expand freely without aecting the other members of the engine, and means for directly fixing said boX-girder on the framework of the aircraft, in place of the usual engine mounting.

ROGER ADOLPHE LEONARD SELIGMAN. 

